Configuring Class-of-Service 113341Configuring Class-of-ServiceThis chapter describes how to configure the Class-of-Service (CoS) feature.The CoS queueing feature lets you directly configure certain aspects of switchqueueing. This provides the desired QoS behavior for different types ofnetwork traffic when the complexities of DiffServ are not required. Thepriority of a packet arriving at an interface can be used to steer the packet tothe appropriate outbound CoS queue through a mapping table. CoS queuecharacteristics that affect queue mapping, such as minimum guaranteedbandwidth, transmission rate shaping, etc., are user-configurable at the queue(or port) level.The topics covered in this chapter include:• CoS Overview• Default CoS Values• Configuring CoS (Web)• Configuring CoS (CLI)• CoS Configuration ExampleCoS OverviewThe CoS feature lets you give preferential treatment to certain types of trafficover others. To set up this preferential treatment, you can configure theingress ports, the egress ports, and individual queues on the egress ports toprovide customization that suits your environment.The level of service is determined by the egress port queue to which thetraffic is assigned. When traffic is queued for transmission, the rate at whichit is serviced depends on how the queue is configured and possibly theamount of traffic present in other queues for that port.Some traffic is classified for service (i.e., packet marking) before it arrives atthe switch. If you decide to use these classifications, you can map this trafficto egress queues by setting up a CoS Mapping table.
